diff --git a/platform/include/internal/platform.h b/platform/include/internal/platform.h
index 7a5aad0..b2915c1 100644
--- a/platform/include/internal/platform.h
+++ b/platform/include/internal/platform.h
@@ -44,9 +44,6 @@ struct tfe_conn_private
 	evutil_socket_t fd;
 	struct bufferevent * bev;
 	uint8_t on_writing;
-	uint8_t closed;
-	uint8_t need_shutdown;
-	struct tfe_stream_write_ctx w_ctx;
 };
 
 struct tfe_stream_private
@@ -59,6 +56,8 @@ struct tfe_stream_private
 	struct tfe_thread_ctx * thread_ref;
 
 	enum tfe_stream_proto session_type;
+	struct tfe_stream_write_ctx * w_ctx_upstream;
+	struct tfe_stream_write_ctx * w_ctx_downstream;
 	struct tfe_conn_private * conn_upstream;
 	struct tfe_conn_private * conn_downstream;
 
diff --git a/platform/src/tcp_stream.cpp b/platform/src/tcp_stream.cpp
index bf86feb..e825076 100644
--- a/platform/src/tcp_stream.cpp
+++ b/platform/src/tcp_stream.cpp
@@ -148,33 +148,77 @@ void tfe_stream_resume(const struct tfe_stream * stream)
 struct tfe_stream_write_ctx * tfe_stream_write_frag_start(const struct tfe_stream * stream, enum tfe_conn_dir dir)
 {
 	struct tfe_stream_private * _stream = to_stream_private(stream);
-	struct tfe_conn_private * this_conn = __this_conn(_stream, dir);
-	struct tfe_conn_private * peer_conn = __peer_conn(_stream, dir);
+	struct tfe_stream_write_ctx ** ref_write_ctx = NULL;
+	struct tfe_conn_private * this_conn = NULL;
+	struct tfe_conn_private * peer_conn = NULL;
 
-	if (this_conn->on_writing == 1)
+	if (dir == CONN_DIR_DOWNSTREAM)
 	{
-		return NULL;
+		this_conn = _stream->conn_downstream;
+		peer_conn = _stream->conn_upstream;
+		ref_write_ctx = &_stream->w_ctx_downstream;
+	}
+	else
+	{
+		this_conn = _stream->conn_upstream;
+		peer_conn = _stream->conn_downstream;
+		ref_write_ctx = &_stream->w_ctx_upstream;
 	}
 
-	this_conn->w_ctx.dir = dir;
-	this_conn->w_ctx._stream = _stream;
+	if (*ref_write_ctx != NULL)
+		return NULL;
+
 	this_conn->on_writing = 1;
+	*ref_write_ctx = ALLOC(struct tfe_stream_write_ctx, 1);
+	(*ref_write_ctx)->_stream = _stream;
+	(*ref_write_ctx)->dir = dir;
+
 	bufferevent_disable(peer_conn->bev, EV_READ);
-	return &(this_conn->w_ctx);
+	return *ref_write_ctx;
 }
 
 int tfe_stream_write_frag(struct tfe_stream_write_ctx * w_ctx, const unsigned char * data, size_t size)
 {
-	struct tfe_conn_private * this_conn = __this_conn(w_ctx->_stream, w_ctx->dir);;
-	int ret = bufferevent_write(this_conn->bev, data, size);
+	struct tfe_conn_private * this_conn = __this_conn(w_ctx->_stream, w_ctx->dir);
+	int ret = 0;
+	if (this_conn != NULL)
+	{
+		ret = bufferevent_write(this_conn->bev, data, size);
+	}
+	else
+	{
+		return -EPIPE;
+	}
+
 	return ret;
 }
+
 void tfe_stream_write_frag_end(struct tfe_stream_write_ctx * w_ctx)
 {
 	struct tfe_conn_private * this_conn = __this_conn(w_ctx->_stream, w_ctx->dir);
 	struct tfe_conn_private * peer_conn = __peer_conn(w_ctx->_stream, w_ctx->dir);
-	this_conn->on_writing = 0;
-	bufferevent_enable(peer_conn->bev, EV_READ);
+
+	if (this_conn != NULL)
+	{
+		this_conn->on_writing = 0;
+		bufferevent_enable(peer_conn->bev, EV_READ);
+	}
+
+	if (w_ctx->_stream != NULL)
+	{
+		if (w_ctx->dir == CONN_DIR_DOWNSTREAM)
+		{
+			assert(w_ctx->_stream->w_ctx_downstream == w_ctx);
+			w_ctx->_stream->w_ctx_downstream = NULL;
+		}
+		else
+		{
+			assert(w_ctx->_stream->w_ctx_upstream == w_ctx);
+			w_ctx->_stream->w_ctx_upstream = NULL;
+		}
+	}
+
+	free(w_ctx);
 }
 
 int tfe_stream_write(const struct tfe_stream * stream, enum tfe_conn_dir dir, const unsigned char * data, size_t size)
@@ -577,7 +621,8 @@ __close_connection:
 
 	if (*ref_this_conn != NULL)
 	{
-		fprintf(stderr, "---- eventcb ----, close this connection, stream = %p, event = %x, dir = %s\n",  _stream, events, __str_dir);	
+		fprintf(stderr, "---- eventcb ----, close this connection, "
+				  "stream = %p, event = %x, dir = %s\n",  _stream, events, __str_dir);
 
 		assert((*ref_this_conn)->on_writing == 0);
 		__conn_private_destory_with_ssl(ev_base, *ref_this_conn, *ref_this_ssl_stream);